| 摘要 |
PURPOSE:To protect a compressor even from a small degree of coolant leakage, by setting the operating pressure of low pressure cut-switch for detecting pressure variations in the coolant to a higher level while connecting a PTC ceramic resistor in parallel with said switch. CONSTITUTION:When closing an ignition switch 6 to close the compressor switch 7, current flows from the power source 9 through each of switches 6-8, and PTC ceramic resistor 4 to electromagnetic clutch 1 thus to turn on said clutch 1 and start the compressor 10 if the thermoswitch 8 provided on an evaporator (not shown) is closed. From this state, the resistor 4 will heat itself and when it reaches to predetermined temperature its resistance increases abruptly thereby the current will scarcely flow through said resistor 4. If the coolant is leaked and the low pressure cut-switch 3 detects the pressure drop and opens, the electromagnetic clutch 1 is turned off to stop the compressor 10. |
